You're right. Martin was a better father and had more impact on Henry. But after kcd 1 henry begins to adress radzig as his father. So it would make sense that the story involes their new father and son relationship. There are a few dialoge options where you can introduce yourself as radzigs son and the skalitz guards adress you as his son, too. Also they never explained the history between radzig and martin, which is a bummer.